The report presents the results of a study conducted by EPA in New England that examined 24 environmental problems and assessed the level of residual risk posed by each problem to human health and to ecosystems. Residual risk is defined as the risk posed by a problem, given current levels of control. The authors also estimated the management tools that are currently available to address the highest risk problem areas. The report summarizes the methodology that was used to conduct these analyses, the findings of the study and lessons learned. The three problems posing the most serious residual risk for human health are ozone, radon and lead. The problems posing the most serious ecological risks are air pollution (primarily ozone), acid rain, loss of wetlands and habitat, all discharges to surface water and accidental releases.